The Radiocarbon Number Behind the Headlines

The specific dates reported in the Paisley research deserve careful attention, because the way those dates are expressed in scientific publications differs from how they are typically reported in popular accounts, and the difference matters for accuracy.

Radiocarbon dating produces dates expressed in radiocarbon years before present, where “before present” is standardly defined as before 1950 CE.

The conversion from radiocarbon years to calibrated calendar years — the conversion required to express the age of a specimen in terms of actual elapsed calendar time — is not a simple linear conversion.

The amount of radiocarbon-14 in the atmosphere has varied over time, and the calibration curve that converts radiocarbon years to calendar years reflects these variations.